1. Technical Field
The present invention relates to a technology that detects the position of a moving body.
2. Related Art
In the related art, there is suggested a technology that detects the position of a moving body such as the rotor of a motor. For example, in JP-A-2004-108774, there is disclosed a configuration of an optical rotary encoder in which a light-receiving element receives light that is transmitted through a plurality of disc slits which operates in connection with the rotation of a motor and in which the angle of rotation of the motor is detected according to an electrical signal that is output from the light-receiving element. The angle of rotation of the motor is computed by an operation that uses the amplitude value of an A-phase sine wave signal and the amplitude value of a B-phase sine wave signal which the light-receiving element outputs.
The technology of JP-A-2004-108774, however, has the problem of a decrease in the accuracy of position detection in that the amplitude value (particularly, the peak-to-peak value) of the electrical signal that the light-receiving element outputs changes due to variations in the speed of rotation of the motor or in the shape of the slits.